Please help me analyze the cause of the circuit failure (containing IGBT)

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Please help me analyze the cause of the circuit failure (containing IGBT) [Copy link]

 

My current plan is to use two IGBTs (1200V, 100A) with the emitters connected together to access the AC path, and control the on and off of the two IGBTs through the driver module VLA517-01R, thereby controlling the on and off of the single-phase AC. The strong power part is shown in the figure below, where the input is AC 220V and the load is a 10W lamp.

But when I powered on the test, the following problems occurred:
When I powered on for the first time, the light bulb just flashed. (This happened twice in a row).
When I powered on for the fourth time, the light bulb remained bright, but it was relatively dim and still flickered. (This happened twice in a row).
When I powered on for the seventh time, the light bulb ran at rated power (very bright), and I realized that the IGBT should have burned out (but now I think that the IGBT withstands a voltage of 1200V, so it shouldn't be that easy to burn out).
The strange thing is that when I tested it, the inversion level did not change the conduction state of the IGBT. In theory, a high level would cause the driver module to output a negative voltage to turn off the IGBT, but in fact it did not output a negative voltage, but a positive voltage of 1.3V (it could only output 4.8V at a low level, not reaching the theoretical 15V). What's even stranger is that it only burned one IGBT, but the light was on normally. After analyzing these phenomena, I felt so contradictory and did not draw any conclusions. Please give me some advice!

maychang

[Control the on and off of two IGBTs through the driver module VLA517-01R]

The [Driver Module VLA517-01R] is not shown in the picture.

maychang

I guess the OP hasn't figured out what voltage means.

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maychang posted on 2024-4-12 16:40 [Control the on and off of two IGBTs through the driver module VLA517-01R] The [driver module VLA517-01R] is not seen in the figure.

J3 corresponds to H2

maychang

Wu Wangmeng published on 2024-4-12 16:55 J3 corresponds to H2

【 J3 corresponds to H2 】

The connection between R5 and R6 is marked Out. Is it connected to pin 3 of U31?

maychang

Wu Wangmeng published on 2024-4-12 16:55 J3 corresponds to H2

【 J3 corresponds to H2 】

Where is pin 1 of H1 connected to in the first picture?

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maychang posted on 2024-4-12 17:29 [J3 corresponds to H2] The connection between R5 and R6 is marked as Out. Is it connected to pin 3 of U31?

Yes

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maychang posted on 2024-4-12 17:30 [ J3 corresponds to H2 ] Where is the 1st pin of H1 connected to in the first post?

Pin 1 of the driver module

maychang

Wu Wangmeng published on 2024-4-12 19:14 Pin 1 of the driver module

【Pin 1 of the driver module】

Pin 1 of the driver module is on one socket H1, but pin 3 is on another socket H2. What is the design of this?

Please post the datasheet of the driver module VLA517-01R.

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maychang posted on 2024-4-12 20:07 [Pin 1 of the driver module] Pin 1 of the driver module is on one socket H1, but pin 3 is on another socket H2. What is this design? Put the driver...

I have two boards arranged on top and bottom for easy connection

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maychang posted on 2024-4-12 20:07 [Pin 1 of the driver module] Pin 1 of the driver module is on one socket H1, but pin 3 is on another socket H2. What is this design? Put the driver...

Driver Module Manual

maychang

Wu Wangmeng published on 2024-4-13 00:01 Driver Module Manual

In the figure on the 4th floor, the power supply for the module VLA517-01R is the 2nd pin of the module VLA517-01R, which is marked as "24V". Its return pin is the 9th pin of the module VLA517-01R, which is grounded (GND) in the figure. In the figure on the 4th floor, the STM32 microcontroller is powered by 5V, and the return is also grounded (GND). In fact, 5V is obtained by stepping down 24V through a 7805. I am afraid that this is the problem.

maychang

Wu Wangmeng published on 2024-4-13 00:01 Driver Module Manual

There are two "N" and "L" in the first picture, which are the two terminals where the AC mains is connected through the load. These two terminals are connected to GND and 24V through a rectifier bridge. So the emitters of the two IGBTs in the first picture (connected to GND) are actually connected to the AC mains through the rectifier bridge, rather than being left floating.

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maychang posted on 2024-4-13 08:11 In the figure on the 4th floor, the 2nd pin of the module VLA517-01R is used to power the module VLA517-01R, and the pin is marked "24V". Its return pin is the analog...

What's the problem here? I don't see it.

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maychang posted on 2024-4-13 08:19 There are two "N" and "L" in the first post, which are the two terminals where the AC mains is connected through the load. These two terminals are connected through a...

The step-down module and IGBT are connected in parallel. Is this connection not allowed?

maychang

Wu Wang Meng posted on 2024-4-13 14:53 What's the problem here? I can't see it.

【What's the problem here? I don't see it. 】

There is no problem here, but when this part of the circuit is put into the overall circuit, there will be problems between this part of the circuit and other parts of the circuit.

The emitter of IGBT is actually connected to GND, and GND is connected to N and L through the rectifier bridge. We know that the diodes on the diagonal of the rectifier bridge are turned on alternately, so the emitter of IGBT is connected to N in half of the AC mains cycle and connected to L in half of the cycle, that is, the emitter of IGBT is connected to the left end of capacitor C5 in half of the cycle and connected to the right end of capacitor C5 in half of the cycle. Look at the schematic diagram in the first post, what will happen?

maychang

Wu Wang Meng posted on 2024-4-13 14:53 The buck module and IGBT are connected in parallel. Is this connection not allowed?

[The buck module and IGBT are connected in parallel]

I really didn’t realize this.

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maychang posted on 2024-4-13 15:26 [What's the problem here? I can't see it. ] There is nothing wrong here, but put this part of the circuit into the overall circuit, this part of the circuit is connected with other...

Those between NL are safety capacitors

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maychang posted on 2024-4-13 15:27 [The buck module and IGBT are connected in parallel] I really didn’t see this.

This is what I think, I don't know if there is anything wrong with the schematic.

maychang

Wu Wang Meng posted on 2024-4-13 15:40 This is what I think, I don’t know if the schematic diagram is drawn correctly.

[This is my idea, I don’t know if the schematic diagram is drawn wrong]

This idea is not wrong, but in this figure the step-down module [220 down to 24V] and the IGBT are not connected in parallel.